Length-Weight Relationships and Condition Factors of Some Fish Species Captured As Non-Target in Crayfish Hunt in Keban Dam Lake

Introduction: The aim of this study is calculate length-weight relationships, length and weight frequency distributions and condition factors of species caught as non-target hunting in crayfish hunting made with pinter at Keban Dam Reservoir. The length-weight relationship is extremely important parameter in terms of fish biology. The length-weight relation parameters (a and b) allow estimation of the weight of the fish from its length and condition index. These values also provide to compare morphologies of populations in different habitats and their life processes (Petrakis ve Stergiou, 1995). Material and Methods: Hunting operations were carried out in Keban, Ağın and Çemişgezek hunting grounds in the Keban Dam Lake between June-August 2012. In operations, crayfish fyke-nets which used prevalently in the region, with D form and 36 mm stretched mesh size, structured with five hoops and a barrier were used. In the hunting operations, additionally crayfishs, Acanthobrama marmid Heckel, 1843, Mastacembelus mastacembelus (Banks&Solander, 1794) and Mystus pelusius (Solander, 1794) were caught as non-target species. The length of fish samples were measured with digital calliper and the weight of fish species were weighed with portable scale. The length-weight relationships were determined with Le Cren’s W= a*Lb equation, condition factor values were calculated from CF= (W*100)/L3 equation (Gulland 1969, Nikolsky 1969, Weatherley 1972, Beverton ve Holt 1957). Results: During the operations, 510 A. marmid, 46 M. mastacembelus and 33 M. pelusius were caught. For each species, length weight relationships, condition factor values and length and weight frequency distributions were determined. For A. marmid, length weight relationship was calculated as W=0.0085TL2.9079 , (r= 0.92); condition factor was estimated as 0.670±0.003. For M. mastacembelus, length weight relationship was computed as W=0.0222TL2.3996 , (r= 0.95); condition factor was determined as 0.215±0.005. For M. pelusius, length weight relationship was counted up as W=0.0333TL2.4555 , (r= 0.71); condition factor was calculated as 0.720±0.022. In all three species, Growth type was determined as “negative allometric”. Discussion: “b” and condition factor values calculated in this study were different from other studies. These differences may result from differences of study areas, catching methods, study times and ecological conditions